1. Field of the Invention
The present invention relates to a string replacement assistance apparatus used when replacing strings in a stringed instrument. More particularly, the present invention relates to an assistance apparatus for facilitating the replacement of strings in a stringed instrument equipped with a tremolo unit.
Priority is claimed on Japanese Patent Application No. 2004-204201, filed Jul. 12, 2004, the content of which is incorporated herein by reference.
2. Description of Related Art
A tremolo unit has been used in a stringed instrument, such as an electric guitar. The tremolo unit supports one ends of strings to obtain a tremolo effect in which the musical interval is minutely increased and decreased by repeatedly changing the tension of the strings in rapid cycles. The structure of such tremolo unit known in the art is shown in FIGS. 9 to 11.
In FIGS. 9 and 10, a tremolo unit 50 is provided on a front surface (an upper surface in FIG. 10) of a body 52 of an electric guitar 51. The tremolo unit 50 includes a bridge base 54 which is pivotally supported by a pair of fulcrum screws or posts 53 on the body 52. The bridge base 54 is provided with a plurality of bridge saddles 56 on its front surface, which secure one end (right-side end in FIG. 10) of associated one of strings 55. An elongated portion 57 is formed on a rear surface (a lower surface in FIG. 10) of the bridge base 54 and located in a recess 52A formed on the body 52. A tension spring 58, such as a coil spring or the like, is connected between a lower edge of the elongated portion 57 and an inner wall of the body recess 52A to be arranged in parallel to the strings 55. The bridge base 54 is further provided with a tremolo arm 60 which is pivotally supported on the front surface of the body 52.
The bridge base 54 makes a pivotal movement around the fulcrum posts 53 in both an arm-up direction A1 and an arm-down direction A2 in FIG. 10 when the tremolo arm 60 is moved in a direction indicated by an arrow R in FIGS. 10 and 11. This pivotal movement of the bridge base 54 changes the tension of the strings to obtain a tremolo effect in which the musical interval is minutely increased and decreased. The tension F1 of the strings 55 when they are attached to the guitar 51 and the spring force F2 of the spring 58 are balanced with respect to a pivotal movement around the fulcrum post 53 so as to hold the bridge base at a position shown in FIG. 10.
The conventional tremolo unit 50 thus structure has the following problems when the strings 55 are replaced. That is, when the tension F1 of the strings 55 is weakened or lost during the replacement of the strings 55, the bridge base 54 takes a position inclined to a direction indicated by an arrow S in FIG. 11 compared with the position in which the strings 55 are attached with the respective tensions as shown in FIG. 10 due to the spring force F2 of the spring 58. Under this condition, one end of a new string is secured to the associated one of the bridge saddle 56 and the other end of the new string is wound up to a turning screw (not shown) on a head of the guitar 51 to apply an appropriate tension for the string. Since the bridge base 54 is inclined in the direction S, it is necessary to wind up the other end of the string to the turning screw many times. Thus, the replacement of the strings is troublesome and takes much time in the stringed instrument equipped with the conventional tremolo unit.